Voltage Stability

Every of the three PSUs is declared to have a very high load capacity of the +5V and +3.3V rails but will they cope with such load in practice?

The 850W model boasts excellent stability of the output voltages throughout the entire load range. None of the voltages violates the permissible limits, and the +12V voltage even stays within a 2% deflection.

The 1000W model’s +5V voltage sags under load. Modern computers do not need a high load capacity of this power rail, though.

Judging by the result of the 1200W model, the previous model was just an unlucky sample. Here, everything is normal. The +3.3V voltage violates the permissible 5% deflection at extreme loads only.

Thus, Chieftec’s Super Series products cope with the loads specified for them, and do that quite easily.

Output Voltage Ripple

This is a really queer oscillogram: the power supply has almost no pulsation on the +12V rail which has almost 90% of the total load during the test. The ripple is far below the allowable maximum on the other two power rails, too.

The 1000W unit shows the same picture: very low pulsation on the +12V and +3.3V rails and notable, yet quite permissible, ripple on the +5V rail.

And we’ve got almost the same picture with the highest-wattage unit at full load. The +12V ripple becomes more conspicuous, yet far within the allowable limits. Moreover, the smooth shape of the pulsation indicates that the manufacturer did not try to save on the quality of the capacitors in the power supply’s output circuitry.